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 ?÷     # Copyright (C) 2001-2010 Python Software Foundation
# Author: Barry Warsaw
# Contact: email-sig@python.org

"""Classes to generate plain text from a message object tree."""
from __future__ import print_function
from __future__ import unicode_literals
from __future__ import division
from __future__ import absolute_import
from future.builtins import super
from future.builtins import str

__all__ = ['Generator', 'DecodedGenerator', 'BytesGenerator']

import re
import sys
import time
import random
import warnings

from io import StringIO, BytesIO
from future.backports.email._policybase import compat32
from future.backports.email.header import Header
from future.backports.email.utils import _has_surrogates
import future.backports.email.charset as _charset

UNDERSCORE = '_'
NL = '\n'  # XXX: no longer used by the code below.

fcre = re.compile(r'^From ', re.MULTILINE)


class Generator(object):
    """Generates output from a Message object tree.

    This basic generator writes the message to the given file object as plain
    text.
    """
    #
    # Public interface
    #

    def __init__(self, outfp, mangle_from_=True, maxheaderlen=None, **_3to2kwargs):
        if 'policy' in _3to2kwargs: policy = _3to2kwargs['policy']; del _3to2kwargs['policy']
        else: policy = None
        """Create the generator for message flattening.

        outfp is the output file-like object for writing the message to.  It
        must have a write() method.

        Optional mangle_from_ is a flag that, when True (the default), escapes
        From_ lines in the body of the message by putting a `>' in front of
        them.

        Optional maxheaderlen specifies the longest length for a non-continued
        header.  When a header line is longer (in characters, with tabs
        expanded to 8 spaces) than maxheaderlen, the header will split as
        defined in the Header class.  Set maxheaderlen to zero to disable
        header wrapping.  The default is 78, as recommended (but not required)
        by RFC 2822.

        The policy keyword specifies a policy object that controls a number of
        aspects of the generator's operation.  The default policy maintains
        backward compatibility.

        """
        self._fp = outfp
        self._mangle_from_ = mangle_from_
        self.maxheaderlen = maxheaderlen
        self.policy = policy

    def write(self, s):
        # Just delegate to the file object
        self._fp.write(s)

    def flatten(self, msg, unixfrom=False, linesep=None):
        r"""Print the message object tree rooted at msg to the output file
        specified when the Generator instance was created.

        unixfrom is a flag that forces the printing of a Unix From_ delimiter
        before the first object in the message tree.  If the original message
        has no From_ delimiter, a `standard' one is crafted.  By default, this
        is False to inhibit the printing of any From_ delimiter.

        Note that for subobjects, no From_ line is printed.

        linesep specifies the characters used to indicate a new line in
        the output.  The default value is determined by the policy.

        """
        # We use the _XXX constants for operating on data that comes directly
        # from the msg, and _encoded_XXX constants for operating on data that
        # has already been converted (to bytes in the BytesGenerator) and
        # inserted into a temporary buffer.
        policy = msg.policy if self.policy is None else self.policy
        if linesep is not None:
            policy = policy.clone(linesep=linesep)
        if self.maxheaderlen is not None:
            policy = policy.clone(max_line_length=self.maxheaderlen)
        self._NL = policy.linesep
        self._encoded_NL = self._encode(self._NL)
        self._EMPTY = ''
        self._encoded_EMTPY = self._encode('')
        # Because we use clone (below) when we recursively process message
        # subparts, and because clone uses the computed policy (not None),
        # submessages will automatically get set to the computed pol